Composition and method for conducting a material removing operation

ABSTRACT

A composition suitable for chemical mechanical polishing a substrate can comprise abrasive particles, a multi-valent metal borate, at least one oxidizer and a solvent. The composition can polish a substrate with a high material removal rate and a very smooth surface finish.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This Application is a continuation of and claims priority under 35U.S.C. § 120 to U.S. patent application Ser. No. 17/004,931, entitled“COMPOSITION AND METHOD FOR CONDUCTING A MATERIAL REMOVING OPERATION,”by Lin F U et al., filed Aug. 27, 2020, which claims priority under 35U.S.C. § 119(e) to U.S. Provisional Application No. 62/894,029, entitled“COMPOSITION AND METHOD FOR CONDUCTING A MATERIAL REMOVING OPERATION,”by Lin F U et al., filed Aug. 30, 2019, which are assigned to thecurrent assignee hereof and are incorporated herein by reference intheir entireties.

FIELD OF THE DISCLOSURE

The present disclosure relates to a composition for conducting amaterial removal operation, specifically a slurry composition includingabrasive particles, a multi-valent metal borate, and an oxidizing agent,and a method of conducting the material removing operation.

BACKGROUND

Abrasive slurries have a large variety of applications, for example, forpolishing of glass, ceramic, or metal materials, and are often designedfor conducting a chemical mechanical planarization (CMP) process. In atypical CMP process, the relative movement of the slurry to a substrateto be polished assists with the planarization (polishing) process bychemically and mechanically interacting with the exterior surface of thesubstrate and removing unwanted material. Polishing is conducted until adesired smooth exterior surface with a low surface roughness isobtained. There exists a need of developing cost efficient abrasiveslurries having a high material removal rate and leading to polishedsubstrates having a low surface roughness.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be better understood, and its numerousfeatures and advantages made apparent to those skilled in the art byreferencing the accompanying drawings.

FIG. 1 includes a graph illustrating the normalized material removal(NMR) of a polishing composition including iron(III)borate according toone embodiment and the NMR of several comparative compositions.

FIG. 2 includes a graph illustrating the NMR of polishing compositionsby varying the amount of oxidizing agent and of iron(III)borateaccording to embodiments.

DETAILED DESCRIPTION

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article, or apparatus that comprises a list of features is notnecessarily limited only to those features but may include otherfeatures not expressly listed or inherent to such process, method,article, or apparatus.

As used herein, and unless expressly stated to the contrary, “or” refersto an inclusive-or and not to an exclusive-or. For example, a conditionA or B is satisfied by any one of the following: A is true (or present)and B is false (or not present), A is false (or not present) and B istrue (or present), and both A and B are true (or present).

Also, the use of “a” or “an” are employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one or at least one and the singular alsoincludes the plural unless it is obvious that it is meant otherwise.

The present disclosure is directed to a composition suitable forconducting a material removing operation. The composition comprisesabrasive particles, a multi-valent metal borate, at least one oxidizingagent and a solvent. It has been surprisingly observed that thecomposition of the present disclosure can conduct polishing of a largevariety of materials, including materials with a high hardness, such assilicon carbide or diamond, with at a high material removal rate and adesired low surface roughness.

As used herein, the term “multi-valent metal” relates to a metalcontaining cation having an oxidation state of +2 or more. As usedherein, the term “multi-valent metal borate” is intended to mean a metalborate compound or complex that includes at least one multi-valent metalcation. It will be appreciated that certain multi-valent metal boratecompounds include only one type of multi-valent metal cation.

For the purpose of calculating the concentrations of the multi-valentmetal borate in the composition, it is assumed that neutral saltsbetween the multi-valent metal ions and the borate ions are formed, forexample, FeBO₃, or AlBO₃, or Cu₃(BO₃)₂.

In one embodiment, a multi-valent metal borate can includeiron(III)borate, copper(II)borate, cobalt(II)borate, bismuth(III)borate,aluminum(III)borate, cerium(III)borate, chromium(III)borate,ruthenium(III)borate, titanium(III)borate, lead(II)borate, or anycombination thereof. In a particular embodiment, the multi-valent metalborate may be iron(III)borate. As used herein, the term“iron(III)borate” is interchangeable used with the terms “iron borate”or “Fe³⁺-borate” or FeBO₃.

In one embodiment, the composition of the present disclosure can be madeby dissolving boric acid (H₃BO₃) and a multi-valent metal salt (e.g., amulti-valent metal nitrate, or chloride, or sulfate salt) in thesolvent, adding and dissolving (at least partially) at least oneoxidizing agent, adding the abrasive particles to form an abrasiveparticle dispersion, and adjusting the pH of the dispersion to a desiredpH. Not being bound to theory, it is assumed that a multi-valent metalborate is formed between the multi-valent metal ion and the borate anionwhich can enhance the polishing efficiency if combined with an oxidizingagent.

In another aspect, the multi-valent metal borate can be formed bydissolving a borate salt having monovalent cations (e.g., sodium borateor potassium borate) together with a multi-valent metal salt (e.g., amulti-valent metal nitrate, or chloride, or sulfate). In another aspect,the multi-valent metal borate can be directly added and dispersed in thesolvent.

In one aspect, the amount of multi-valent metal borate in thecomposition can be at least 0.01 wt % based on the total weight of thecomposition, or at least 0.025 wt %, or at least 0.05 wt %, or at least0.1 wt %, or at least 0.5 wt %, or at least 1 wt %, or at least 2 wt %,or at least 3 wt %. In another aspect, the amount of the multi-valentmetal borate may be not greater than 50 wt % based on the total weightof the composition, or not greater than 40 wt %, or not greater than 30wt %, or not greater than 20 wt %, or not greater than 10 wt %, or notgreater than 5 wt %, or not greater than 4 wt %, or not greater than 3wt %, or not greater than 2 wt %, or not greater than 1 wt %, or notgreater than 0.5 wt %, or not greater than 0.1 wt %. The amount of themulti-valent metal borate can be a value between any of the minimum andmaximum values noted above, such as at least 0.025 wt % and not greaterthan 5 wt %, or at least 0.05 wt % and not greater than 1 wt %, or atleast 0.05 wt % and not greater than 0.2 wt % based in the total weightof the composition.

In one non-limiting embodiment, the composition may have a molar ratioof total multi-valent metal-ions to total boron within a range of 1:20to 20:1 (metal:boron), which means it may have either an excess ofmulti-valent metal ions or an excess of borate ions. In one embodiment,the molar ratio of total multi-valent metal-ions to total boron can beat least 1:18, or at least 1:15, or at least 1:12, or at least 1:10, orat least 1:9, or at least 1:8, or at least 1:7, or at least 1:6, or atleast 1:5, or at least 1:4, or at least 1:3, or at least 1:2. In anotherembodiment, the ratio of total multi-valent metal-ions to total boronmay be not greater than 18:1, or not greater than 15:1, or not greaterthan 12:1, or not greater than 10:1, or not greater than 9:1, or notgreater than 8:1, or not greater than 7:1, or not greater than 6:1, ornot greater than 5:1, or not greater than 4:1, or not greater than 3:1or not greater than 2:1, or not greater than 1:1.

In one aspect, the molar ratio of total multi-valent metal ions to totalboron can be used to calculate a molar ratio of total multi-valent metalions to total borate ions, which can be within the same range as theratios noted above for total multi-valent metal ions to total boron. Forexample, in one non-limiting embodiment, the ratio of total multi-valentmetal ions to total borate ions may be within a range of 1:20 to 20:1.It will be understood that such a calculation may be based upon anassumption that all boron in the composition is in the form of borateions.

In one embodiment, the oxidizing agent contained in the composition ofthe present disclosure can be a compound which dissolves in the solventand has a suitable oxidation potential for chemically reacting with asurface of a substrate either alone or in combination with themulti-valent metal borate contained in the composition. It has beensurprisingly observed that the efficiency of an oxidizing agent can begreatly enhanced if a multi-valent metal borate is further contained inan abrasive slurry composition. Not to be bound to theory, it is assumedthat a synergistic effect is obtained by the multi-valent metal borateand the oxidizing agent when chemically altering the surface of asubstrate material during polishing.

In one aspect, the oxidizing agent can have an oxidation potential of atleast 0.26V, or at least 0.4V, or at least 0.5V, or at least 1.0V, or atleast 1.5V. In another aspect, the oxidation potential may be notgreater than 2.8V, or not greater than 2.5V, or not greater than 2.0V.As used herein, the oxidation potential is the value measured relativeto the standard hydrogen electrode, at a temperature of 25° C., apressure of 1 atm, at a concentration of 1 mol/L of the tested compoundin water, and measured in Volt (V).

Non-limiting examples of oxidizing agents can be, for example, aperoxide, a permanganate, a peroxydisulfate, a chlorite, a perchlorate,a hypochlorite, an iodate, a periodate, a nitrite, a hyponitrite, achromate, manganese oxide, or any combination thereof. In a particularembodiment, the oxidizing agent can be selected from potassiumpermanganate, hydrogen peroxide, potassium peroxydisulfate, or anycombination thereof.

The amount of the oxidizing agent in the composition can be at least0.01 wt % based on the total weight of the composition, or at least 0.05wt %, or at least 0.1 wt %, or at least 0.05 wt %, or at least 1.0 wt %,or at least 1.5 wt %, or at least 2 wt %, or at least 3 wt %. In anotheraspect, the amount of oxidizing agent can be not greater than 40 wt %,such as not greater than 30 wt %, not greater than 20 wt %, not greaterthan 10 wt %, not greater than 7 wt %, not greater than 5 wt %, notgreater than 3 wt %, not greater than 2 wt %, not greater than 1 wt %,or not greater than 0.5 wt % based on the total weight of thecomposition. The amount of the oxidizing agent can be a value betweenany of the minimum and maximum values noted above, such as at least 0.01wt % and not greater than 10 wt %, or at least 1 wt % and not greaterthan 5 wt % based on the total weight of the composition.

In a particular embodiment, the solvent of the composition of thepresent disclosure can be water, but is not limited thereto. In otheraspects, the solvent can be a mixture of water and one or more otherpolar and/or unpolar solvents.

The abrasive particles contained in the composition of the presentdisclosure are not limited to a specific material type and can include,for example, zirconia, alumina, silica, diamond, cubic boron nitride,ceria, iron oxide, titanium oxide, manganese oxide, lanthanium oxide, orany combination thereof. In a particular aspect, the abrasive particlescan be selected from alumina, zirconia, ceria, silica, diamond, or ironoxide. In one certain aspect, the abrasive particles can be alumina. Inanother certain aspect, the abrasive particles can be zirconia.

The average size (D50) of the abrasive particles can be at least 10 nm,or at least 25 nm, or at least 50 nm, at least 80 nm, at least 100 nm,at least 130 nm, or at least 150 nm, at least at least 180 nm, or atleast 200 nm, or at least 250 nm. In another embodiment, the averageparticle size may be not greater than 50 microns, such as not greaterthan 20 microns, not greater than 10 microns, not greater than 5microns, not greater than 1 micron, not greater than 0.8 microns, notgreater than 0.5 microns, or not greater than 0.3 microns. The averageparticle size of the abrasive particles can be a value between any ofthe minimum and maximum values noted above, for example, at least 50 nmand not greater than 500 nm, at least 70 nm and not greater than 250 nm,or at least 80 nm and not greater than 200 nm.

In one embodiment, the amount of the abrasive particles contained in thecomposition can be at least 0.01 wt % based on a total weight of thecomposition, or at least 0.05 wt %, or at least 0.1 wt %, or at least0.5 wt %, or at least 1 wt %, or at least 2 wt %, or at least 3 wt %, orat least 4 wt %, or at least 5 wt %. In another embodiment, the amountof the abrasive particles can be not greater than 50 wt %, such as notgreater than 40 wt %, or not greater than 30 wt %, or not greater than20 wt %, or not greater than 15 wt %, or not greater than 10 wt %, ornot greater than 8 wt %, or not greater than 5 wt %. The amount ofabrasive particles can be a value between any of the minimum and maximumvalues noted above. In a particular aspect, the amount of abrasiveparticles can be at least 0.1 wt % and not greater than 5 wt %.

In embodiments, the composition can further comprise one or moreoptional additives, for example a surfactant, or a dispersant, or achelating agent, a pH buffer, a rheology modifier, a corrosion resistantagent, or any combination thereof.

In a certain embodiment, the composition of the present disclosure canconsist essentially of abrasive particles, iron borate, a permanganatesalt, and water.

The pH of the composition can be within a range of at least 1 and notgreater than 9. In certain aspects, the pH can be at least 1.3, or atleast 1.5, or at least 1.7, or at least 1.9, or at least 2.0. In otheraspects, the pH of the composition may be not greater than 8.5, such asnot greater than 8, or not greater than 7, or not greater than 5, or notgreater than 4, or not greater than 3.5, or not greater than 3.0, or notgreater than 2.5, or not greater than 2.3. The pH of the composition canbe a value between any of the minimum and maximum values noted above,such as at least 1 and not greater than 9, at least 1.5 and not greaterthan 5, or at least 1.8 and not greater than 2.5.

The present disclosure is further directed to a method of polishing asubstrate. The method can comprise: providing the polishing compositionof the present disclosure described above, bringing the polishingcomposition in direct contact with the substrate; and polishing thesubstrate surface. In one aspect, the substrate can be polished with apolishing pad, wherein the polishing pad and the substrate are movingrelative to one another and the polishing composition is in contact withthe substrate and the polishing pad.

In one embodiment, the temperature of the polishing composition duringpolishing can be at least 40° C., or at least 45° C., or at least 50°C., or at least 55° C., or at least 60° C., or at least 65° C.

In another embodiment, the temperature of the composition duringpolishing may be not greater than 90° C., or not greater than 85° C., ornot greater than 80° C., or not greater than 75° C., or not greater than70° C. The temperature of the composition during polishing can be avalue in a range between any of the minimum and maximum values notedabove.

It has been surprisingly discovered that the composition of the presentdisclosure can be suitable as a chemical mechanical polishingcomposition having a high polishing efficiency of a substrate andleading to a smooth exterior surface of the polished substrate with alow surface roughness.

In one embodiment the substrate to be polished can include a ceramicmaterial, a metal, a metal alloy, diamond, or a polymer. In a particularembodiment, the substrate can be a group III-V compound, for example,gallium nitride. In another particular embodiment, the substrate can bea group IV-IV compound, for example, silicon carbide. Non-limitingexamples of a polymer can be a polyacrylate, a polymethacrylate, apolyimide, a polyolefine, a polyacrylamide, a polyester, a polyurethane,or any combinations, such as co-polymers or cross-polymers thereof, asused, e.g., in a photo-resist.

In a particular aspect, the composition and method of the presentdisclosure can be adapted for polishing a silicon carbide substrate witha normalized removal rate of at least 1.5 and a surface roughness of notgreater than 2.0 Å. As used herein, the normalized material removal rateis the ratio of the actual removal rate of the slurry to the removalrate of a baseline slurry, wherein the baseline slurry contains 1 wt %alpha alumina particles with an average particle size of 100 nm, 4 wt %KMnO₄, 95 wt % distilled water, and is adjusted to the same pH as theslurry to be tested. In a particular embodiment, the normalized materialremoval rate of polishing a silicon carbide substrate can be at least1.6, at least 1.7, at least 1.8, at least 1.9, at least 2.0, at least2.1, at least 2.2, or at least 2.3. In another aspect, the surfaceroughness of the silicon carbide substrate after polishing can be notgreater than 1.9 Å, or not greater than 1.8 Å, or not greater than 1.7Å, or not greater than 1.6 Å, or not greater than 1.5 Å.

In another embodiment, the present disclosure is directed to a kitadapted to preparing a composition for chemical mechanical polishing,and a method of polishing a substrate using the kit. The kit cancomprise a first package and a second package (herein also called“two-package kit”), wherein the first package may comprise amulti-valent metal salt, and the second package may comprise boric acid.It has been surprisingly observed that a polishing composition preparedby the two-package kit can have over a longer time period a desiredpolishing efficiency than a composition which contains all ingredientsin one package. Not being bound to theory, it is assumed that formingthe multi-valent metal borate in-situ, short before conducting apolishing operation, may have an advantage.

In one aspect, the shelf-life of the two-package kit can be at least 70days, such as at least 80 days, at least 100 days, at least 150 days, atleast 200 days, or at least 365 days. As used herein, the shelf-life ofthe kit is defined as the amount of days that the two-package kit isstored at room temperature, wherein a composition prepared by combiningthe first package and the second package of the kit has a decline in thepolishing efficiency of polishing a silicon carbide substrate of atleast 16% in comparison to the polishing efficiency of a correspondingcomposition prepared from the two-package kit with the shelf life of oneday.

The kit, after combining the first package and the second package, cancorrespond to the same composition as described above for polishing asubstrate, having the same properties and features. In one aspect, theabrasive particles can be contained in the first package or the secondpackage of the kit. In yet another aspect, the at least one oxidizingagent can be contained in the first package or the second package of thekit. In a particular aspect, the abrasive particles and the at least oneoxidizing agent may be contained together with the boric acid andsolvent in the first package, while the second package can contain themulti-valent metal salt and solvent.

As further demonstrated in the Examples below, the present disclosureprovides compositions suitable as abrasive slurries for polishing asubstrate, and particularly for chemical mechanical polishing asubstrate.

Many different aspects and embodiments are possible. Some of thoseaspects and embodiments are described herein. After reading thisspecification, skilled artisans will appreciate that those aspects andembodiments are only illustrative and do not limit the scope of thepresent invention. Embodiments may be in accordance with any one or moreof the embodiments as listed below.

EMBODIMENTS

Embodiment 1. A composition comprising: abrasive particles; amulti-valent metal borate; at least one oxidizing agent; and a solvent.

Embodiment 2. The composition of Embodiment 1, wherein the multi-valentmetal borate includes iron(III)borate, copper(II)borate,cobalt(II)borate, bismuth(III)borate, aluminum(III)borate,cerium(III)borate, chromium(III)borate, ruthenium(III)borate,titanium(III)borate, lead(II)borate, or any combination thereof.

Embodiment 3. The composition of Embodiment 2, wherein the multi-valentmetal borate includes iron(III)borate, copper(II)borate,cobalt(II)borate, bismuth(III)borate, aluminum(III)borate,cerium(III)borate, or any combination thereof.

Embodiment 4. The composition of Embodiment 3, wherein the multi-valentmetal borate consists essentially of iron(III)borate.

Embodiment 5. The composition of any of the preceding Embodiments,wherein the composition comprises a molar ratio of total multi-valentmetal-ions to total boron within a range of 1:20 to 20:1.

Embodiment 6. The composition of Embodiment 5, wherein the molar ratioof total multi-valent metal-ions to total boron is at least 1:18, or atleast 1:15, or at least 1:12, or at least 1:10, or at least 1:9, or atleast 1:8, or at least 1:7, or at least 1:6, or at least 1:5, or atleast 1:4, or at least 1:3, or at least 1:2.

Embodiment 7. The composition of Embodiment 5, wherein the molar ratioof total multi-valent metal-ions to total boron is within a range of notgreater than 18:1, or not greater than 15:1, or not greater than 12:1,or not greater than 10:1, or not greater than 9:1, or not greater than8:1, or not greater than 7:1, or not greater than 6:1, or not greaterthan 5:1, or not greater than 4:1, or not greater than 3:1 or notgreater than 2:1, or not greater than 1:1.

Embodiment 8. The composition of any of the preceding Embodiments,wherein an oxidation potential of the at least one oxidizing agent is atleast 0.26 V, or at least 0.4 V, or at least 0.5 V, or at least 1.0 V,or at least 1.5 V.

Embodiment 9. The composition of any of the preceding Embodiments,wherein an oxidation potential of the at least one oxidizing agent isnot greater than 2.8 V.

Embodiment 10. The composition of any of the preceding Embodiments,wherein the at least one oxidizing agent includes a peroxide, apermanganate, a peroxydisulfate, a chlorite, a perchlorate, ahypochlorite, a nitrite, a hyponitrite, an iodate, a periodate, achromate, manganese oxide, or any combination thereof.

Embodiment 11. The composition of Embodiment 10, wherein the oxidizingagent consists essentially of a permanganate.

Embodiment 12. The composition of Embodiment 11, wherein thepermanganate is potassium permanganate.

Embodiment 13. The composition of any of the preceding Embodiments,wherein an amount of the multi-valent metal borate is at least 0.01 wt%, or at least 0.025 wt %, or at least 0.05 wt % or at least 0.1 wt % orat least 0.5 wt % or at least 1 wt %, or at least 2 wt %, or at least 3wt % based on the total weight of the composition.

Embodiment 14. The composition of any of the preceding Embodiments,wherein an amount of the multi-valent metal borate is not greater than50 wt %, or not greater than 40 wt %, or not greater than 30 wt %, ornot greater than 20 wt %, or not greater than 10 wt %, or not greaterthan 5 wt %, or not greater than 4 wt %, or not greater than 3 wt %, ornot greater than 2 wt %, or not greater than 1 wt %, or not greater than0.5 wt %, or not greater than 0.1 wt % based on the total weight of thecomposition.

Embodiment 15. The composition of Embodiments 13 or 14, wherein anamount of the multi-valent metal borate is at least 0.01 wt % and notgreater than 5 wt %, or at least 0.03 wt % and not greater than 1 wt %,or at least 0.05 wt % and not greater than 0.2 wt % based in the totalweight of the composition.

Embodiment 16. The composition of any of the preceding Embodiments,wherein an amount of the at least one oxidizing agent is at least 0.01wt % based on the total weight of the composition, or at least 0.05 wt%, or at least 0.1 wt %, or at least 0.05 wt %, or at least 1.0 wt %, orat least 1.5 wt %, or at least 2 wt %, or at least 3 wt %.

Embodiment 17. The composition of any of the preceding Embodiments,wherein an amount of the at least one oxidizing agent is not greaterthan 40 wt %, such as not greater than 30 wt %, not greater than 20 wt%, not greater than 10 wt %, not greater than 7 wt %, not greater than 5wt %, not greater than 3 wt %, not greater than 2 wt %, not greater than1 wt %, or not greater than 0.5 wt % based on the total weight of thecomposition.

Embodiment 18. The composition of Embodiments 16 or 17, wherein theamount of the at least one oxidizing agent is at least 0.01 wt % and notgreater than 10 wt %, or at least 1 wt % and not greater than 5 wt %based on the total weight of the composition.

Embodiment 19. The composition of any of the preceding Embodiments,wherein the solvent includes water.

Embodiment 20. The composition of any of the preceding Embodiments,wherein the abrasive particles include zirconia, alumina, silica,diamond, cubic boron nitride, ceria, iron oxide, titanium oxide,manganese oxide, lanthanium oxide, or any combination thereof.

Embodiment 21. The composition of Embodiment 20, wherein the abrasiveparticles include alumina, zirconia, ceria, silica, diamond, or ironoxide.

Embodiment 22. The composition of Embodiment 21, wherein the abrasiveparticles include zirconia.

Embodiment 23. The composition of Embodiment 21, wherein the abrasiveparticles include alumina.

Embodiment 24. The composition of any of the preceding Embodiments,wherein an average (D50) particle size of the abrasive particles is atleast 25 nm, or at least 50 nm, at least 80 nm, at least 100 nm, atleast 150 nm, at least 200 nm, or at least 250 nm.

Embodiment 25. The composition of any of the preceding Embodiments,wherein an average (D50) particle size of the abrasive particles is notgreater than 50 microns, such as not greater than 20 microns, notgreater than 10 microns, not greater than 5 microns, not greater than 1micron, not greater than 0.8 microns, not greater than 0.5 microns, ornot greater than 0.3 microns.

Embodiment 26. The composition of any of the preceding Embodiments,wherein an average (D50) particle size of the abrasive particles is atleast 50 nm and not greater than 250 nm.

Embodiment 27. The composition of any of the preceding Embodiments,wherein an amount of the abrasive particles is at least 0.01 wt % basedon a total weight of the composition, at least 0.05 wt %, or at least0.1 wt %, or at least 0.5 wt %, or at least 1 wt %, or at least 2 wt %,or at least 3 wt %, or at least 4 wt %, or at least 5 wt %.

Embodiment 28. The composition of any of the preceding Embodiments,wherein an amount of the abrasive particles is not greater than 50 wt %,such as not greater than 40 wt %, not greater than 30 wt %, not greaterthan 20 wt %, not greater than 15 wt %, not greater than 10 wt %, notgreater than 8 wt %, or not greater than 5 wt %.

Embodiment 29. The composition of any of the preceding Embodiments,wherein an amount of the abrasive particles is at least 0.1 wt % and notgreater than 5 wt %.

Embodiment 30. The composition of any of the preceding Embodiments,wherein a pH of the composition is at least 1 and not greater than 9, orat least 1.5 and not greater than 5, or at least 1.8 and not greaterthan 2.5.

Embodiment 31. The composition of any of the preceding Embodiments,wherein a pH is at least 1.3, at least 1.5, at least 1.7, at least 1.9,at least 2.0, at least 2.1, at least 2.2, at least 2.3, at least 2.4, orat least 2.5.

Embodiment 32. The composition of any of the preceding Embodiments,wherein a pH is not greater than 4, or not greater than 3.8, or notgreater than 3.5, or not greater than 3.2, or not greater than 3.0, ornot greater than 2.8, or not greater than 2.5, or not greater than 2.3.

Embodiment 33. The composition of any of the preceding Embodiments,wherein the composition is adapted for chemical mechanical polishing ofa substrate.

Embodiment 34. The composition of Embodiment 33, wherein the substrateincludes a ceramic material, a metal, a metal alloy, diamond, or apolymer.

Embodiment 35. The composition of Embodiment 34, wherein the ceramicmaterial includes a group III-V compound or a group IV-IV compound.

Embodiment 36. The composition of Embodiment 35, wherein the ceramicmaterial includes gallium nitride or silicon carbide.

Embodiment 37. The composition of any of the preceding Embodiments,wherein the composition further comprises a surfactant, or a dispersant,or a chelating agent, or a pH buffer, or a rheology modifier, or acorrosion resistant agent, or any combination thereof.

Embodiment 38. The composition of any of the preceding Embodiments,consisting essentially of the abrasive particles, iron borate, apermanganate salt, and water.

Embodiment 39. The composition of any of the preceding Embodiments,wherein the composition is adapted for polishing a silicon carbidesubstrate with normalized removal rate of at least 1.5 and a surfaceroughness of not greater than 2.0 Å.

Embodiment 40. The composition of Embodiment 39, wherein the normalizedremoval rate is at least 1.6, at least 1.7, at least 1.8, at least 1.9,at least 2.0, at least 2.1, at least 2.2, or at least 2.3.

Embodiment 41. The composition of Embodiment 39, wherein the surfaceroughness after polishing the silicon carbide substrate is not greaterthan 1.9 Å, or not greater than 1.8 Å, or not greater than 1.7 Å, or notgreater than 1.6 Å, or not greater than 1.5 Å.

Embodiment 42. A method of polishing a substrate, comprising: providinga polishing composition, wherein the polishing composition comprisesabrasive particles, a multi-valent metal borate, at least one oxidizingagent and water; bringing the polishing composition in contact with thesubstrate; and polishing the substrate.

Embodiment 43. The method of Embodiment 42, wherein the substrateincludes a ceramic material, a metal, a metal alloy, diamond, or apolymer, a group III-V compound, or a IV-IV compound.

Embodiment 44. The method of Embodiment 43, wherein the substrate issilicon carbide or gallium nitride.

Embodiment 45. The method of Embodiment 42, further including adjustingthe polishing composition before polishing to a pH of at least 1 and notgreater than 9.

Embodiment 46. The method of Embodiment 45, wherein the pH is adjustedto a pH of at least 1 and not greater than 5.

Embodiment 47. The method of Embodiment 46, wherein the pH is at least1.3, at least 1.5, at least 1.7, at least 1.9, at least 2.0, at least2.1, at least 2.2, at least 2.3, at least 2.4, or at least 2.5.

Embodiment 48. The method of Embodiment 46, wherein the pH is notgreater than 4, or not greater than 3.8, or not greater than 3.5, or notgreater than 3.2, or not greater than 3.0, or not greater than 2.8, ornot greater than 2.5, or not greater than 2.3.

Embodiment 49. The method of any of Embodiments 42-48, wherein polishingis conducted at a normalized removal rate of the substrate of at least2.0.

Embodiment 50. The method of any of Embodiments 42-49, wherein a surfaceroughness of the substrate after polishing is not greater than 2 Å.

Embodiment 51. The method of any of Embodiments 42-50, wherein theabrasive particles include zirconia, alumina, silica, diamond, cubicboron nitride, ceria, iron oxide, titanium oxide, manganese oxide,lanthanium oxide, or any combination thereof.

Embodiment 52. The method of Embodiment 51, wherein the abrasiveparticles include alumina, zirconia, ceria, silica, diamond, or ironoxide.

Embodiment 53. The method of any of Embodiments 42-52, wherein anoxidation potential of the at least one oxidizer is at least 0.26 V, orat least 0.4 V, or at least 0.5 V, or at least 1.0 V, or at least 1.5 V.

Embodiment 54. The method of any of Embodiments 42-53, wherein theoxidation potential of the oxidizer is not greater than 2.8 V.

Embodiment 55. The method of any of Embodiments 42-54, wherein the atleast one oxidizing agent includes a peroxide, a persulfate, apermanganate, chlorite, a nitrite, a perchlorate, a hypochlorite,manganese oxide, or any combination thereof.

Embodiment 56. The method of Embodiment 55, wherein the oxidizing agentconsists essentially of a permanganate.

Embodiment 57. The method of Embodiment 56, wherein the permanganate ispotassium permanganate.

Embodiment 58. The method of any of Embodiments 42-57, wherein an amountof the multi-valent metal borate is at least 0.01 wt % and not greaterthan 5 wt %, or at least 0.05 wt % and not greater than 1 wt %, or atleast 0.05 wt % and not greater than 0.3 wt % based in the total weightof the composition.

Embodiment 59. The method of any of Embodiments 42-58, wherein theamount of the oxidizing agent is at least 0.01 wt % and not greater than10 wt %, or at least 0.5 wt % and not greater than 5 wt % based on thetotal weight of the composition.

Embodiment 60. The method of any of Embodiments 42-59, wherein thesolvent includes water.

Embodiment 61. The method of any of Embodiments 42-60, wherein a pH ofthe composition is at least 1 and not greater than 9, or at least 1.5and not greater than 5, or at least 1.8 and not greater than 2.5.

Embodiment 62. The method of any of Embodiments 42-61, wherein the pH isat least 1.3, at least 1.5, at least 1.7, at least 1.9, at least 2.0, atleast 2.1, at least 2.2, at least 2.3, at least 2.4, or at least 2.5.

Embodiment 63. The method of any of Embodiments 42-62, wherein the pH isnot greater than 4, or not greater than 3.8, or not greater than 3.5, ornot greater than 3.2, or not greater than 3.0, or not greater than 2.8,or not greater than 2.5, or not greater than 2.3.

Embodiment 64. A kit adapted to preparing a composition for chemicalmechanical polishing, the kit comprising a first package and a secondpackage, wherein the first package comprises a multi-valent metal salt,and the second package comprises boric acid.

Embodiment 65. The kit of Embodiment 64, wherein the kit is adapted thatafter combining package 1 and package 2 a multi-valent metal borate isformed in-situ.

Embodiment 66. The kit of Embodiments 64 or 65, wherein the firstpackage or the second package further comprises abrasive particles.

Embodiment 67. The kit of any one of Embodiments 64-66, wherein thefirst package or the second package further comprises at least oneoxidizing agent.

Embodiment 68. The kit of Embodiment 64, wherein the second packagefurther comprises abrasive particles and at least one oxidizing agent.

Embodiment 69. The kit of any one of Embodiments 64-67, wherein themulti-valent metal ion of the multi-valent metal salt includes Fe³⁺,Fe²⁺, Co²⁺, Ce³⁺, Bi³⁺, Al³⁺, Ru³⁺, Ti³⁺, Pb²⁺, or any combinationthereof.

Embodiment 70. The kit of Embodiment 69, wherein the multi-valent metalion includes Fe³⁺ or Cu²⁺.

Embodiment 71. The kit of Embodiment 70, wherein the multi-valent metalion consists essentially of Fe³⁺.

Embodiment 72. The kit of any one of Embodiments 64-71, wherein thefirst package is essentially free of boron.

Embodiment 73. The kit of any one of Embodiments 64-72, wherein an anionof the multi-valent metal salt includes nitrate, chloride, bromide,iodide, sulfate, phosphate or any combination thereof.

Embodiment 74. The kit of any one of Embodiments 64-73, wherein the atleast one oxidizing agent includes a permanganate, a peroxydisulfate, achlorite, a perchlorate, a hypochlorite, a nitrite, a hyponitrite, aniodate, a periodate, a chromate, a peroxide, manganese oxide, or anycombination thereof.

Embodiment 75. The kit of Embodiment 74, wherein the at least oneoxidizing agent includes a permanganate salt.

Embodiment 76. The kit of Embodiment 75, wherein the at least oneoxidizing agent includes potassium permanganate.

Embodiment 77. The kit of any one of Embodiments 66-76, wherein theabrasive particles include alumina particles, zirconia particles, or acombination thereof.

Embodiment 78. The kit of any one of Embodiments 64-77, wherein the kithas a shelf-life of at least 70 days, the shelf-life corresponding tothe amount of days that a composition prepared from the kit by combiningthe first package and the second package has a decline in polishingefficiency of at least 16% in comparison to a polishing efficiency ofthe composition after one day of preparing the kit.

Embodiment 79. The kit of Embodiment 78, wherein the shelf-life of thekit is at least 80 days, or at least 100 days, or at least 150 days, orat least 200 days, or at least 365 days.

Embodiment 80. A method of polishing a substrate, comprising: preparinga polishing composition, wherein preparing the polishing compositioncomprises combining a first package and a second package, the firstpackage and the second package being parts of a kit, wherein the firstpackage comprises a multi-valent metal salt and the second packagecomprises boric acid; bringing the polishing composition in contact withthe substrate; and polishing the substrate.

Embodiment 81. The method of Embodiment 80, wherein combining the firstpackage and the second packages comprises in-situ forming of amulti-valent metal borate.

Embodiment 82. The method of Embodiments 80 or 81, wherein preparing thepolishing composition is conducted on the same day as the polishing ofthe substrate.

Embodiment 83. The method of any one of Embodiments 80-82, wherein thefirst package or the second package further comprises abrasiveparticles.

Embodiment 84. The method of Embodiment 83, wherein the abrasiveparticles include alumina particles or zirconia particles.

Embodiment 85. The method of any one of Embodiments 80-84, wherein thefirst package or the second package further comprises at least oneoxidizing agent.

Embodiment 86. The method of Embodiment 80, wherein the second packagefurther comprises abrasive particles and at least one oxidizing agent.

Embodiment 87. The method of any one of Embodiments 80-85, wherein themulti-valent metal ion of the multi-valent metal salt includes Fe³⁺,Fe²⁺, Co²⁺, Ce³⁺, Bi³⁺, Al³⁺, Ru³⁺, Ti³⁺, Pb²⁺, or any combinationthereof.

Embodiment 88. The method of Embodiment 87, wherein the multi-valentmetal ion includes Fe³⁺ or Cu²⁺.

Embodiment 89. The method of Embodiment 88, wherein the multi-valentmetal ion consists essentially of Fe³⁺.

Embodiment 90. The method of any one of Embodiments 80-89, wherein thefirst package is essentially free of boron.

Embodiment 91. The method of any one of Embodiments 80-90, wherein ananion of the multi-valent metal salt includes nitrate, chloride,bromide, iodide, phosphate, sulfate, or any combination thereof.

Embodiment 92. The method of any one of Embodiments 80-91, furtherincluding any one of the features of Embodiments 46-63.

EXAMPLES

The following non-limiting examples illustrate the present invention.

Example 1

An aqueous abrasive slurry composition (S1) was prepared by adding to945 ml distilled water under stirring 2.5 g (6.19 mmol) iron(III)nitratenonahydrate (Fe(NO₃)3 9H₂O), 2.5 g (40.3 mmol) boric acid (H₃BO₃), 40.0g (253.2 mmol) potassium permanganate (KMnO₄) and 10 g alpha aluminaparticles having a mean (D50) particle size of 100 nm from Saint-Gobain.After combining all ingredients, the pH of the slurry was adjusted with1N HNO₃ to a pH of 2.1. According to the molar amounts of the addedingredients, the molar ratio of total Fe³⁺ ions to total borate ions(BO₃ ³⁻) was 1:6.5.

Furthermore, slurries were prepared the same way as slurry S1, but usingdifferent types of multi-valent metal nitrates in order to form thefollowing multi-valent metal borates: Al³⁺-borate (slurry S2);Cu²⁺-borate (slurry S3); Bi³⁺-borate (slurry S4); Co²⁺-borate (slurryS5); Ce³⁺-borate (slurry S6); Ni²⁺-borate (slurry C7) and Ag⁺-borate(comparative slurry C3).

The polishing properties of the slurries were tested and compared bypolishing a silicon carbide substrate using a Strasbaugh 6EC PolishingTool. The silicon carbide substrate was a 4H-type round wafer with adiameter of 150 mm.

A summary of the tested slurry compositions and the test results, suchas the normalized material removal rate and surface roughness afterpolishing, can be seen in Table 1.

TABLE 1 Slurry Abrasive Metal- Metal-Ions H₃BO₃ KMnO₄ Surface No.particles Ions [mmol/kg] [mmol/kg] mmol/kg pH NMR Roughness [Å] S1alumina Fe³⁺ 6.19 40.3 253.2 2.1 2.26 1.6 S2 alumina Al³⁺ 6.19 40.3253.2 2.1 1.70 1.5 S3 alumina Cu²⁺ 6.19 40.3 253.2 2.1 1.72 1.6 S4alumina Bi³⁺ 6.19 40.3 253.2 2.1 1.82 1.5 S5 alumina Co²⁺ 6.19 40.3253.2 2.1 1.57 1.5 S6 alumina Ce³⁺ 6.19 40.3 253.2 2.1 1.40 1.4 S7alumina Ni²⁺ 6.19 40.3 253.2 2.1 0.98 1.4 C1 alumina Fe³⁺ 6.19 — 253.22.1 1.53 1.6 C2 alumina Fe³⁺ —   40.3− 253.2 2.1 1.33 1.5 C3 alumina Ag⁺6.19 40.3 253.2 2.1 1.06 1.5

The polishing test results for the different slurry compositionssummarized in Table 1 show that the highest normalized removal rate(NMR) was obtained for slurry S1, which contained the combination ofalumina particles, iron borate, KMnO₄ and water.

It can be further seen that with other multi-valent metal borates, suchas Al³⁺ borate, Cu²⁺ borate, Bi³⁺ borate, Co²⁺ borate, and Ce³⁺ borate,although the normalized material removal rate was lower than the NMR ofthe iron borate containing slurry S1, the NMR was still at least 40%higher than the removal rate of the corresponding base line slurry(containing 1 wt % alumina, 4 wt % KMnO₄, 95 wt % water, pH 2.1).

As also illustrated in FIG. 1 , comparative slurries C1 and C2demonstrate that the presence of only Fe³⁺-ions and no borate ions(comparative slurry C1) and of only borate ions and no Fe³⁺-ions(comparative slurry C2) resulted in a much lower NMR as obtained withslurry S1 including iron borate. Not to be bound to theory, thesecomparisons indicate the synergistic effect of iron borate with theoxidizing agent as a major reason for the high NMR, while slurriescontaining oxidizer with boric acid alone (C2) or oxidizer and Fe³⁺-ionsalone (C1) were much lower in the material removal rate. In addition,sample S1 also contributed to an excellent surface finish.

A comparative slurry including Ag+ borate (see comparative slurry C3),as an example of a mono-valent metal borate, had a NMR which was aboutthe same as the removal rate of the baseline slurry and did not providean advantage regarding the removal rate during polishing, see also FIG.1 .

The normalized removal rate (NMR) was calculated as the ratio betweenthat actual material removal rate of the tested slurry and the removalrate of a corresponding baseline slurry, also called herein baselineremoval rate. The baseline removal rate was measured with a standardslurry containing 1 wt % alpha alumina particles with an average size of100 nm from Saint-Gobain, 4 wt %, KMnO₄, and 95 wt % distilled water,adjusted to pH=2.1. When measuring the baseline removal rate, the samepolishing conditions were used as for the slurry of interest.

Example 2

In Example 2, a slurry composition was prepared and tested including asabrasive particles 1 wt % zirconia with an average particle size of 100nm from Saint-Gobain. Except to the change of the type of abrasiveparticles, the slurry containing zirconia abrasive particles (S8)contained the same ingredients and was prepared the same way as slurryS1 of Example 1.

As summarized in Table 2, it can be seen that slurry S8, which includedzirconia particles, iron borate and KMnO₄, had an even higher NMR thanslurry S1, which contained alumina particles instead of zirconiaparticles.

Comparative slurry composition C4, which contained only zirconiaparticles and oxidizer KMnO₄, lead to a NMR which was similar as thebaseline slurry containing alumina particles.

The high NMR of 2.61 with slurry S8 versus a NMR 0.97 of the comparativeslurry not including a multi-valent metal borate, demonstrates again thesurprising effect of the combination of iron borate and oxidizing agentwith regard to the polishing efficiency. The experiments further showthat the type of abrasive particles contained in the slurry appears tohave a rather minor influence on the NMR in comparison to the effect ofthe presence of the iron borate.

TABLE 2 Normalized Surface Slurry Abrasive Metal- Metal-Ions H₃BO₃ KMnO4removal rate Roughness No. particles Ions [mmol/kg] [mmol/kg] [mmol/kg]pH (NMR) [Å] S8 zirconia Fe³⁺ 6.19 40.3 253.2 2.1 2.61 1.3 S1 aluminaFe³⁺ 6.19 40.3 253.2 2.1 2.26 1.6 C4 zirconia — — — 253.2 2.1 0.97 1.3

Example 3

In Example 3, iron borate containing slurries were investigated withregard to varying the amount of alumina particles.

As summarized in Table 3 below, doubling the amount of alumina from 1 wt% (slurry S1) to 2 wt % (slurry S9) resulted in an increase of the NMRof 0.28.

TABLE 3 Normalized Surface Slurry Abrasive Me- Me-Ion Borate removalRoughness No. particles Ion [mmol/kg] [mmol/kg] Oxidizer pH rate (NMR)[Å] S1 1 wt % Fe³⁺ 6.19 40.3 KMnO₄ 2.1 2.26 1.6 alumina S9 2 wt % Fe³⁺6.19 40.3 KMnO₄ 2.1 2.54 1.6 alumina

Example 4

In Example 4, the NMR of a slurry containing two oxidizing agents (S10)was compared with slurry S1, which contained only one oxidizing agent.The only difference between the two slurries was the additionaloxidizing agent.

As shown in Table 4 below, adding in addition to the KMnO₄ as a secondoxidizing agent potassium peroxydisulfate (K₂S₂O₈) in an amount of 9.26mmol/kg, resulted in a minor increase of the NMR by 0.22.

TABLE 4 Normalized Surface Slurry Abrasive Me- Me-Ion Borate removalRoughness No. particles Ion [mmol/kg] [mmol/kg] Oxidizer pH rate (NMR)[Å] S1 1 wt % Fe³⁺ 6.19 40.3 KMnO₄ 2.1 2.26 1.6 alumina S10 1 wt % Fe³⁺6.19 40.3 KMnO₄ + 2.1 2.48 1.6 alumina K₂S₂O₈

Example 5

Slurry compositions with varying concentrations of iron borate andoxidizer KMnO4 were compared to investigate the influence on the NMR ofsilicon carbide. All NMR testing was conducted the same way as inExample 1, and also included the same baseline slurry (1 wt % alphaalumina particles, 4 wt % KMnO₄, 95 wt % water and a pH of 2.1).

The measured NMR of the slurries and the obtained surface roughness ofthe silicon carbide substrate after the polishing is summarized in Table5.

In slurry S11, the amount of iron borate and the amount of oxidizingagent was reduced to half the amount compared to slurry S1 of Example 1,which resulted in a decrease of the NMR from 2.26 (sample S1) to 1.75(sample S11). It was highly surprising to observe in this experimentthat a relatively large reduction in the amount of oxidizer (4 wt % to 2wt %) reduced the NMR only from 2.26 to 1.75, and resulted in a veryminor change of the final surface roughness. This demonstrates again thesynergistic effect of iron borate and oxidizer during the polishing,wherein an amount of only 0.04 wt % iron borate (3.4 mmol/kg FeBO₃)together with about 2 wt % KMnO₄ (126.6 mmol/kg) was capable ofincreasing the removal rate by 75% in comparison to the baseline slurry,wherein the baseline slurry contained twice the amount of the oxidizerMKnO₄ (4 wt %).

TABLE 5 Slurry Abrasive Fe³⁺ Borate Ratio of KMnO4 Surface No. particles[mmol/kg] [mmol/kg] Fe³⁺/Borate [mmol/kg] NMR Roughness[Å] S1 alumina6.19 40.3 1:6.5 253.2/ 2.26 1.6 (0.074 wt %) (4 wt %) S11 alumina 3.4022.2 1:6.5 126.6 1.75 1.6 (0.035 wt %) (2 wt %) S12 alumina 6.19 40.31:6.5  63.3 1.24 2.2 (0.074 wt %) (1 wt %) S13 alumina 0.619 4.03 1:6.5253.2 1.19 1.4 (0.007 wt %) (4 wt %) C5 alumina 0.619 4.03 1:6.5  63.30.48 1.4 (0.0074 wt %) (1 wt %)

The polishing results for slurry S12 demonstrate that lowering theamount of KMnO₄ to a fourth of the amount used in slurry S1 (from 4 wt %(S1) to 1 wt % (S11)), but keeping the amount of iron borate the same asin S1, caused a strong decrease of the NMR from 2.26 to 1.24, see alsoFIG. 2 . This result indicates again that the oxidizing agent plays inaddition to the iron borate an important role for the material removalefficiency of the slurries, and both ingredients, iron borate andoxidizer, appear to work synergistically together. The example showsthat if the amount of oxidizer reaches a certain minimum amount, itcannot be compensated by increasing the amount of iron borate.

As further shown in FIG. 2 , lowering the amount of iron borate inslurry S13 to a tenth and keeping the amount of oxidizing agent the sameas in slurry S1, also caused a strong decrease of the NMR from 2.26 to1.19. This also indicates that both iron borate and the oxidizer areneeded to provide a synergistic effect. It is remarkable, however, thatslurry sample S13 had a higher NMR than the baseline slurry, showingthat iron borate even at concentrations of 0.0074 wt % (0.619 mmol/kg)can have an effect on improving the polishing efficiency if combinedwith KMnO₄ in the same concentration amount as contained in the baselineslurry.

In comparative slurry C5, a four times lower amount of KMnO4 was used asin slurry S1, and furthermore the amount of iron borate was reduced to atenth of the amount as in slurry S1. In this situation, the NMR of theslurry was worse than the removal rate of the baseline slurry used tocalculate the NMR.

Description of the Polishing Testing:

All polishing slurries of the examples of the present disclosure weretested for the their influence on the material removal rate of 4°off-axis silicon carbide wafers using a Strasbaugh 6EC single sidedpolishing tool.

The polishing was conducted under the following conditions:

Platen diameter (inches) 22.0 Runtime (min) 10.0 Down force (psi) 9.0Platen speed (rpm) 103 Head speed (rpm) 123 PV(Down force · Platenspeed) 533.9 lbs/in · s PV (Down force · Platen speed) 9554 kg/m · sHead speed/platen speed 1.19 Flow (ml/min) 48 flow rate/platen area0.126 ml/in² min Polishing pad IC1000

The substrates polished were 4H-type silicon carbide (4° off-axis)wafers having a diameter of 150 mm and a thickness of 350 μm. Thematerial removal rate was calculated from the weight loss measured withan Ohaus Explorer Model FX324 precision scale.

The surface roughness was measured with a Zygo New View 8300+ scanningoptical profiler.

A baseline removal rate in μm/hour was measured before the testing ofeach slurry and was conducted with the following base-slurry: 1 wt %alpha alumina (from Saint-Gobain), 4 wt % KMnO₄, 95 wt % distilledwater, adjusted to the pH of the slurry to be tested (which was in mostslurries a pH of 2.1, except indicated otherwise). After measuring thebaseline removal rate, the polishing efficiency of the investigatedslurry was measured in μm/hour. For the calculation of the normalizedremoval rate (NMR), the actual material removal rate of the testedslurry (MRR) was divided by the baseline removal rate (BRR).

A summary of the measured actual material removal rates (MRR), thecorresponding baseline removal rates (BRR) (measured always before thetesting of a slurry composition), and the calculated normalized removalrate (NMR), with NMR=MMR/BRR, for all slurry compositions S1 to S13 andcomparative slurries C1 to C5 are shown in Table 6.

TABLE 6 Actual Material Baseline Material Normalized Removal RateRemoval Rate Material Slurry (MRR) (BRR) Removal Rate No. [μm/hr][μm/hr] [NMR] S1 3.88 1.72 2.26 S2 3.64 2.14 1.70 S3 3.84 2.23 1.72 S44.05 2.23 1.82 S5 3.71 2.36 1.57 S6 3.12 2.23 1.40 S7 2.03 2.07 0.98 S85.81 2.23 2.61 S9 4.32 1.70 2.54 S10 4.22 1.70 2.48 S11 2.47 1.41 1.75S12 2.91 2.34 1.24 S13 3.08 2.58 1.19 C1 2.77 1.81 1.53 C2 2.00 1.501.33 C3 2.52 2.37 1.06 C4 2.17 2.23 0.97 C5 0.75 1.56 0.48

Example 6

Two-Package Kit.

A kit is prepared including two packages. The first package includesFe(NO₃)₃ and water. The second package of the kit includes aluminaparticles, KMnO₄, boric acid, and water. The amount of the ingredientsin each package is adjusted that after the combination of package 1 withpackage 2, without adding further water and without adjusting the pH,the polishing composition (Sample S14) made from the kit contains 4 wt %KMnO₄, 1.25 wt % boric acid, 0.2 wt % alumina particles, and 1.25 wt %Fe(NO)₃. The pH of the obtained polishing composition is 2.1.

The kit is tested for its polishing efficiency of polishing a siliconcarbide substrate after different amount of days storage at roomtemperature. Fluid compositions are prepared from the two-package kit asdescribed above after 20 days, 40 days, 50 days, and 70 days storage ofthe two-package kit. There is no decline observed in the polishingefficiency (material removal rate) of the fluid compositions made fromthe kit within the time frame of 70 days.

In the foregoing specification, the concepts have been described withreference to specific embodiments. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the invention as set forth in theclaims below. Accordingly, the specification and figures are to beregarded in an illustrative rather than a restrictive sense, and allsuch modifications are intended to be included within the scope of theinvention.

What is claimed is:
 1. A kit adapted for preparing a composition forpolishing a substrate, the kit comprising a first package and a secondpackage, wherein the first package comprises a multi-valent metal salt,and the second package comprises boric acid, and wherein the firstpackage or the second package comprises at least one oxidizing agent. 2.The kit of claim 1, wherein the first package or the second packagecomprises abrasive particles.
 3. A kit adapted for preparing acomposition for polishing a substrate, the kit comprising a firstpackage and a second package, wherein the first package comprises amulti-valent metal salt, and the second package comprises boric acid,and wherein the second package comprises abrasive particles and at leastone oxidizing agent.
 4. The kit of claim 1, wherein the multi-valentmetal ion of the multi-valent metal salt includes Fe³⁺, Fe²⁺, Co²⁺,Ce³⁺, Bi³⁺, Al³⁺, Ru³⁺, Ti³⁺, Pb²⁺, or any combination thereof.
 5. Thekit of claim 4, wherein the multi-valent metal ion includes Fe³⁺ orCu²⁺.
 6. The kit of claim 5, wherein the multi-valent metal ion consistsessentially of Fe³⁺.
 7. The kit of claim 1, wherein the first package isessentially free of boron.
 8. The kit of claim 1, wherein an anion ofthe multi-valent metal salt includes nitrate, chloride, bromide, iodide,sulfate, phosphate, or any combination thereof.
 9. The kit of claim 1,wherein the at least one oxidizing agent includes a permanganate salt.10. The kit of claim 9, wherein the at least one oxidizing agentincludes potassium permanganate.
 11. The kit of claim 2, wherein theabrasive particles include alumina particles, zirconia particles, or acombination thereof.
 12. A kit comprising a first package and a secondpackage, wherein the kit is adapted that after combining the firstpackage and the second package a composition is obtained, thecomposition comprising abrasive particles, a multi-valent metal borate,at least one oxidizing agent and a solvent.
 13. The kit of claim 12,wherein the at least one oxidizing agent is a permanganate salt.
 14. Thekit of claim 13, wherein the permanganate salt includes potassiumpermanganate.
 15. The kit of claim 12, wherein the multi-valent metalborate of the composition after combining the first package and thesecond package includes iron(III)borate, copper(II)borate,cobalt(II)borate, bismuth(III)borate, aluminum(III)borate,cerium(III)borate, chromium(III)borate, ruthenium(III)borate,titanium(III)borate, lead(II)borate, or any combination thereof.
 16. Thekit of claim 15, wherein the multi-valent metal borate includesiron(III)borate or copper(II)borate.
 17. The kit of claim 12, whereinthe first package comprises a multi-valent metal salt, and the secondpackage comprises boric acid, and wherein the first package isessentially free of boron.
 18. The kit of claim 12, wherein the abrasiveparticles include alumina particles, zirconia particles, or acombination thereof.
 19. The kit of claim 12, wherein an amount of theabrasive particles of the composition is at least 0.1 wt % and notgreater than 10 wt % based on the total weight of the composition. 20.The kit of claim 3, wherein the at least one oxidizing agent includes apermanganate salt.